Carrier 40RU 25, Manual

Page: 28 / 40

28
Pulley and Drive Adjustment
To obtain desired fan speed, refer to the fan motor, drive data and
performance data in Tables 13-26 and adjust fan motor pulley as
follows:
1. Remove belt from fan motor pulley after loosening motor
from motor base.
2. Loosen setscrew in moveable flange of pulley. Screw
moveable flange toward fixed flange to increase the fan speed
and away from fixed flange to reduce speed. Before tighten -
ing setscrew, make certain that setscrew is over nearest flat
surface of pulley hub. (See Fig. 27.)
Condensate Drains
Keep condensate drains free of dirt and foreign matter.
Return-Air Filters
Refer to Replacing Filters section for filter accessibility and re -
moval. Replace with clean filters of the sizes listed in Tables 1-6.
Chilled Water Coil Freeze Protection
Shut off water supply to unit. Remove side panel of unit and re -
move vent and drain plugs in top and bottom of coil header. Drain
coil and blow out remaining water. Reinstall plugs and side panel.
Alternative freeze protection methods follow:
• Circulate hot water within the water coil’s supply main or
supplementary space heating.
• Close off supply lines to unit and open a union or field-
supplied drain valve in the return line.
• After draining as much water as possible from coils, add
sufficient antifreeze to prevent residual water in the coil
from freezing.
• Add a sufficient quantity of non-corrosive antifreeze to the
entire system to prevent all water within the system from
freezing.
Coil Removal
Remove unit panels and corner posts as required. Disconnect coil
connections and remove fastening screws. Remove coil through
end or side sections of unit.
Cleaning Cooling Coil
Remove return-air filters. Remove any heavy dirt that may have
accumulated on underside of coil. Coil can be cleaned more easily
with a stiff brush, vacuum cleaner, or compressed air when coil is
dry. If coil is wet or if water is to be used for cleaning, guard
against splashing water on electrical components or damaging sur -
rounding area. Clean coil baffles as applicable and check for tight
fit to be sure air does not bypass coil.
Cleaning Insulation
The insulation contains an immobilized antimicrobial agent that
helps inhibit the growth of bacteria and fungi. Clean the inner
surface of the insulation according to the separate maintenance
instructions shipped with the unit.
Replacing Filters
Filters can be removed and installed from either side of the unit.
Install new filters in units that have one fan as follows:
1. Remove the side access panel (retain screws).
2. Remove the filter retainer clip (see Fig. 28).
3. Remove old filters by lifting and tilting them out of the filter
track. (See Fig. 16 and 29.) Use the factory-supplied filter
hook to slide filters within reach for removal. The filter hook
is shipped inside the unit in the filter track.
4. Reverse the procedure to install new filters.
Fig. 28 — Remove Filter Retainer Clip
Fig. 29 — Filter Removal/Replacement
CAUTION
UNIT OPERATION HAZARD
Failure to follow this caution could cause equipment damage.
Increasing fan speed produces a greater load on motor.
Do not exceed rated capacity of motor.
IMPORTANT: Draining from return line will not completely
drain water from coils.
CAUTION
UNIT OPERATION HAZARD
Failure to follow this caution could cause equipment damage.
Do not operate unit without air filters.
Slide
Filter
Retainer
Clip